Tube bending machine with rotating former and means for moving a wiper bar in an orbit at twice the angular speed of the former



2,817,384 MEANS FOR ANGULAR SPEED OF THE FORMER Filed June 22, 1953 A 4 Shets-Sheet 1 INVENTOR Fig. I.

p A E F m 3 Y B Dec. 24; 1957 T L MABERY 2,817,384

TUBE BENDING MACHINE W ITI- I ROTATING FORMER AND MEANS FOR MOVING A WIPER BAR IN AN ORBIT AT TWICE THE 7 Filed June 22. 1953 Fig. 2.

ANGULAR SPEED OF THE FORMER 4 Sheets-Sheet 2 INVENTOR Thomas L. Mcbery A EY Dec. 24, 1957 L. MABERY 2,817,384

TUBE BENDING MACHINE WITH ROTATING FORMER AND MEANS FOR MOVING A WIPER BAR IN AN ORBIT AT TWICE THE ANGULAR SPEED OF THE FORMER Filed June 22. 1955 I 4 Sheets-Sheet 5 INVENTOR Thomas L, Mubery SMiWM ATTORNEY T. L. 'MABERY Dec. 24, 1957 2,817,384 TUBE BENDING MACHINE WITH ROTATING FORMER AND MEANS FOR MOVING A WIPER BAR IN AN ORBIT ATTWICE THE ANGULAR SPEED OF THE FORMER Filed June 22, 1953 4 Sheets-Sheet 4 INVENTOR Thomas L. Mubery 21 ATT V EY United rates Patent TUBE BENDING MACHINE WITH ROTATING FORMER AND MEANS FOR MOVING A WIPER BAR IN AN ORBIT AT TWICE THE ANGULAR SPEED OF THE FORMER Thomas L. Mabery, Chattanooga, Tenn, assignor to Combustion Engineering, Inc., New York, N. Y., a corporation of Delaware Application June 22, 1953, Serial No. 363,195 2 Claims. (Cl. 153-39) This invention relates to apparatus for bending metallic tubes and particularly to a machine for forming a U-bend in a tube from which a bifurcated or Y-tube is to be subsequently formed by attaching an extension piece to the elbow region of the bend.

One method that has been developed for forming bifurcated tubes is to create along the length of a piece of tubing a bulge at one side of its axis to provide sufiicient metal to create a neck to which an extension tube may be welded to form a bifurcated tube after the bulged workpiece has been bent so that tube legs lie parallel to each other with the elbow region of the bend including the bulge from which the neck is created to attach the extension. Machines for bending tubes to create a 180 degree bend therein are quite old and generally utilize a rotary bending former to which the tube is attached and around which it is bent as a bending former rotates while the tube is pressed against the latter, in some cases by a follower bar. However, such apparatus is not suitable for use in bending the above mentioned bulged tubular workpiece from which a bifurcate is to be formed for a number of reasons. Primary among these reasons is that it is Clifi'lClllt, if not impossible, to maintain the bulge centered during the operation so that it comes out in the median plane of the bend which is parallel to the axis of the tubes. A further disadvantage results from the fact that the outer region of the tube in forming a 180 degree bend has to move through a 180 degree are at a faster rate than the crotch region of the tube because of the larger radius and consequent greater circumferential traverse. As a result, the outer wall of the tube is thinned to an undesirable degree while at the same time the tube material tends to pile up in the crotch region of the bend in such manner as to partially obstruct the fluid passage.

The main object of the present invention is to provide a bending machine which may be utilized to form 180 degree bends in metallic workpieces which are provided with eccentric bulges intermediate their ends without involving the disadvantages set forth above. The invention will be best understood upon consideration of the following detailed description of an illustrative embodiment thereof when read in conjunction with the accompanying drawings in which:

Figure 1 is a simplified plan view of a bending machine embodying the present invention.

Figure 2 is an elevational view as viewed in the direction of the arrows 22 in Figure l and illustrates the driving apparatus for the bending machine.

Figure 3 is a sectional elevation on the line 33 in Figure 1 and shows the mechanism for driving the bending former and a wiper bar at different speeds.

Figures 4a to 4e are diagrammatic views illustrating the relative positions of the tube and the basic parts of the bending machine including the bending former and wiper bar in their relative positions during formation of the 180 degree bend, Figure 4a showing the tube and parts of the machine at the start of the bending operation.

Figure 4b shows the relative positions of the parts when the bending former has moved approximately 22 degrees or somewhat less than a third of its traverse in the bending cycle.

Figures 4c and 4d illustrate the parts during subsequent steps in the bending operation while Figure 4e shows the bent tube and the parts of the bending machine when the degree bend has been completed.

Referring first to Figure 1, the basic elements of the bending machine consist of the rotary bending former 10 around which the tube is formed, the wiper bar 12 which forces or pushes the tube around the bending former and the follower bar 13 which maintains the advancing portion of the tube in contact with the bending former and guides the advancing portions of the tube in their movement to and around the bending former 10. A shaft 14 (Figure 2) driven by a motor (not shown) is provided with a gear 16 having half as many teeth as the meshing gear 18 so that a second shaft 20 is driven at half the speed of the shaft 14. The shaft 20 acts through a worm 22 and worm gear 24 to drive the spindle 26 to which a worm gear 24 is secured (Figure 3) so as to turn the bending former iii. The shaft 14 acting through the worm 3i and worm gear 32 turns a sleeve 34 concentric with the shaft 26 to rotate the wiper bar 12 about the bending former 10 but at twice the speed of movement of the latter because of the ratio between the gears 16 and 1.8. The wiper bar 12 is mounted on a slide 35 mounted in guides 36 supported on the table 38 which is carried by the rotary supporting structure 40 mounted to turn about the axis of shaft 26, the structure 40 being rotatably mounted at 42 so that the entire supporting structure ill carrying the table 38 and wiper bar 12 rotates with but relatively to the bending former 10, moving in a circular orbit or path relatively to the latter.

The bending former 1b is horizontally divided into upper and lower parts 5t}, 52 (Figure 3 so that a hydraulic cylinder 54 acting through suitable linkages may raise a rod 56 so as to elevate the upper half 50 of the bending former It with respect to the lower half 52 in order to facilitate ready insertion and removal of a workpiece between the bending quadrant and the wiper bar 12 and follower bar 13. The two halves of the bending former in and also the opposite face of the wiper bar 12 have semi-circular recesses as indicated at 57 and 58 in Figure 2 so as to receive the tubular workpiece therebetween. he face of the follower bar 13 contacting the workpiece is similarly recessed. The slide for the wiper bar 12 is connected through the link 60 and piston rod 62 with a hydraulic cylinder 64 so that the wiper bar 12 may be slid in and out on its guides 36 on the table 38 with respect to the bending former 10. The follower bar 13 is similarly connected with the slide 66 and is reciprocal in guides 68 by another hydraulic cylinder which is not illustrated because the arrangement is similar to the cylinder 64 for the slide 35 of the wiper bar.

Prior to the bending operation the workpiece A (Figure 4a) from which a bifurcate tube is to be made has an eccentric bulge B formed therein by any suitable known method so as to provide material for a neck to attach an extension in the elbow region of the 180 degree tube bend from which the bifurcate is constructed. When the upper half 50 of the bending former 10 has been raised and the wiper bar 12 and follower bar 13 drawn away from the bending former by their hydraulic mechanisms, the workpiece A is inserted in position against the lower half 52 of the bending former with the upset or bulge B located along the axis of the tube in the position between the wiper bar 12 and follower bar 13. When the tube which was previously .heated in the region C of the bulge is positioned in the machine as described above, the upper half 50 of the bending former is lowered and the hydraulic mechanisms present the wiper bar 12 and the follower bar 13 against the side of the tube opposite the bending former 10. Then when the motor driving the shaft 14 is rendered effective the wiper bar 12 pushes the tube in an are around the bending former 10 which moves at half the speed of the wiper bar since the latter being on the outer radius has twice the distance to go to form a 180 degree bend as the portion of the tube in contact with the bending former 10, which part moves through only 90 degrees during the bending operation. As the length or leg A of the tube is forced around the bending former 10 by the wiper bar 12, the tube length D at the other side of the bulge B trails along and is pressed against the bending former by the follower bar 13. The latter also is drawn along with the tube as may be seen by comparing Figures 4a and 4b with Figures 4c and 4d which illustrate later stages in the bending operation. Due to the fact that the wiper bar 12 moves at twice the rate of the bending former 10, the parts of the tube move about the bending former 10 at rates corresponding to their positions on larger bending arcs so that the tube portion B at the end of the bending operation is centered on the elbow of the 180 degree bend and is not offcentered because of being retarded by the wiper bar 12 and as would occur in the event that the wiper bar 12 and the bending former 10 moved at the same rate of speed. When the tube has been bent to 180 degrees as represented in Figure 40, it may be then removed from themachine by elevating the upper half of the bending former 10 and retracting the wiper bar 12 and the follower bar 13 after the latter have been returned to their starting positions by reversing the direction of drive of the spindle 26 and sleeve 34. In a subsequent operation the bulge B is opened at its outer end and an extension piece attached to form the Y bifurcate as indicated in dotted lines for purposes of illustration in Figure 42.

What I claim is:

1. A tube bending machine comprising; a curved bending former; a wiper bar and an axially aligned follower bar mounted confronting the latter and spaced apart to receive between their adjacent ends an eccentrically bulged portion protruding from one side of a tubular workpiece, the other side of said bulged portion of the tubular workpiece being positioned to tangentially abut said bending former, the bending former, the wiper and follower bars having work faces corresponding to the external surface of the tubular workpiece adjacent said bulged portion; means for urging said faces of the wiper bar and follower bar toward the bending former to maintain the workpiece pressed tangentially against said faces of the bending former; means for rotating said bending former through a determined bending arc; and means for simultaneously moving said wiper bar in an orbit about the bending former at twice the speed of movement of the latter so that it traverses an are double that of the bending former.

2. A tube bending machine comprising; a curved bending former; a wiper bar and an axially aligned follower bar mounted opposite the bending former and spaced apart to receive between their adjacent ends an eccentrically bulged portion protruding from one side of a tubular workpiece, the other side of said bulged portion of the tubular workpiece being positioned to tangentially abut said bending former, the bending former, the wiper and follower bars having work faces corresponding to the external surface of the tubular workpiece adjacent said bulged portion; means for urging said faces of the wiper bar and follower bar toward the bending former to maintain the workpiece pressed tangentially against said faces of the bending former; means for rotating said bending former through an arc of degrees; and means for simultaneously moving said wiper bar in an orbit about the bending former at twice the speed of movement of the latter so that it carries the portion of the workpiece in engagement therewith through a bending arc of degrees while the bending former moves through a 90 degree are.

References Cited in the file of this patent UNITED STATES PATENTS 588,223 Fowler Aug. 17, 1897 1,052,069 Lassiter Feb. 4, 1913 1,914,810 Kraeft June 20, 1933 2,148,748 Hardy Feb. 28, 1939 2,223,0l5 Hathorn Nov. 26, 1940 2,241,414 Morris May 13, 1941 2,651,349 Smith Sept. 8, 1953 FOREIGN PATENTS 457,101 France July 4, 1913 

